Comparative study on the seismic performance of high strength steel composite K-eccentrically braced frames

The seismic performance of K-shaped high-strength steel composite eccentrically braced frames (K-HSS-EBFs) with the combinations of different strength grades of steel and number of stories was investigated. Three groups of K-HSS-EBFs including 10, 15, and 20 stories were designed, and a dynamic time-history analysis was performed using 10 seismic ground motion records. The rotation angles and plastic strain of the links and the story drift angles of the samples under different earthquake levels were obtained. The results show that the story drift angle distribution of K-HSS-EBFs along the height of the structure is consistent with that of conventional K-shaped steel eccentrically braced frame structures. Under 8-degree rare earthquakes, the story drift angle of K-HSS-EBFs meets the specification limit. K-HSS-EBFs have good energy dissipation and sufficient load-carrying capacity. The seismic action that the structure can withstand and the link rotation angle obtained in Q690-X are larger compared with those of conventional K-shaped eccentrically braced frames. It is conservative to use the specification limit of the elastic-plastic story drift angle as a control index in the design. The performance based seismic design(PBSD) method can ensure that the links in eccentrically braced steel frame structures enter into the plastic state during rare earthquakes while other members remain elastic, thereby highlighting the energy-dissipation effect of the link in eccentrically braced frame structures. © 2021, Editorial Office of Journal of Vibration and Shock. All right reserved.